TNG 2011: Solid-State Transformers Part II

Eric Wesoff is Editor-at-Large at Greentech Media. Prior to joining GTM, Eric Wesoff founded Sage Marketing Partners in 2000 to provide sales and marketing-consulting services to venture-capital firms and their portfolio companies in the alternative energy and telecommunications sectors. Mr. Wesoff has become a well-known, respected authority and speaker in these fields.

His expertise covers solar power, fuel cells, biofuels and advanced batteries. His strengths are in market research and analysis, business development and due diligence for investors. He frequently consults for energy startups and Silicon Valley's premier venture capitalists.

"The grid really equals smart power electronics. It's not even about the networks." He added, "We need a whole new class of devices and systems. A 50-year-old transformer made of copper wire wound around a ferrite core can't respond to a signal, so we can't control it," adding, "If we invest in new power electronics devices, things will change radically. The design of existing systems will change based on these new components."

Here's advice to entrepreneurs, according to Vinod Khosla: "We have to focus on power electronics."

This panel at The Networked Grid event focused on power electronics, specifically solid-state transformers (SSTs).

The legacy transformer is one of the most integral building blocks of the utility distribution grid, though very little R&D has gone into improving these ubiquitous and crucial devices. As Khosla stated, utilities have limited monitoring and/or control capabilities for these or other critical grid assets beyond the substation. As power generation becomes distributed and intermittent, and as EV loads proliferate, the need for software-based intelligence, frequency and voltage regulation, remote monitoring, control, management, automated actuation, harmonic filtering and other features will be required.

Next-generation solid-state transformers, engineered with intelligent power electronics, versus traditional, static coil-based transformers are being developed to provide these features and integrate many disparate grid asset functions, such as voltage regulators, cap banks, reclosers, switches, storage, etc.

Naimish Patel, the CEO of Gridco Systems spoke of reducing magnetics, simply because of the inevitable rise of commodities prices and the need to reduce iron, copper, and steel. Reduced usage of these commodities will reduce cost, size and volume. Current applications are in submarines and ships, but as cost comes down, these devices will proliferate in the grid. SSTs have the potential for greater power density, adaptability, and performance compared to traditional transformers.

Gary Rackliffe, Vice President, Smart Grids Operations, at ABB, one of the largest transformer players in the world, spoke of SSTs and their ability to manage voltage regulation, unbalanced loads, power factor, and harmonics.

There is no doubt that SSTs are currently priced higher than traditional transformers, but the functionality and controllability they offer can provide value throughout the network. Military and specialized applications will be the first to use these components.

David Grider, Program Manager, Silicon Carbide Power Devices at Cree, sees the silicon carbide material providing ten times better performance than silicon, with much higher switching times and better performance than silicon IGBTs.

According to ABB's Rackliffe, today's utilities perform "procurement based on one piece of apparatus at time -- not on a systems basis." But as Patel put it, once you build a transformer with this architecture, you get enormous benefits -- and that value has to be counted. The net impact is that you can look at the distribution grid from end to end. Digital technology simply provides much-needed modularity and adaptability. SSTs can also extend the life of other components in the system by exposing them to less stress.

With the advent of solid-state transformers, voltage transformation (the primary function of a transformer to step up/down voltage) becomes only one of many new features. When you start to consider many of the other potential features surrounding voltage regulation (CVR, programmable output voltage, OV protection for PV-centric circuits, etc.); power quality (reactive power compensation and harmonic filtering); management and telemetry (integrated remote management, real-time load management, active line analysis, etc.); and other functions (such as the option for integrated storage); it becomes evident that these new integrated devices are much more than yesterday's transformers.

Proponents of solid-state transformers are not suggesting a rip-and-replace strategy for existing transformers. The strategy for the introduction of solid-state transformers will center around strategic benefits related to the 'green circuit' of the future, rolling out devices on feeders with high PV penetration and EV load. In addition, most utilities have a relatively well-known annual replacement strategy (often in the 2 percent to 4 percent range) for aging transformers, failures, etc., providing another opportunity to introduce smarter devices, enabling a beneficial network effect as more devices are rolled out over time. The idea is to get the initial devices in place where pain points exist and then build a more intelligent platform over time. International markets may provide significant greenfield opportunities where power quality is a major issue.

Despite advances in AMI and other early smart grid deployments, it's becoming clear that we are in the very early stages of a truly intelligent grid. Until the embedded intelligence of these higher-layer control plane architectures is integrated into grid assets sitting in the power plane, the grid is only partially intelligent. Although there are enhanced sensors and monitoring technologies being introduced into the power layer of the smart grid, it's only the beginning, as true real-time decision making and actuation is what will ultimately be required.

Solid-state transformers, and the many additional features and benefits they bring, have the potential to be a cornerstone device for such functionality.

In Patel's view, this needs to be looked at as a fundamental change in today's grid -- moving it from the current analog system to a more modular and adaptable digital system.